Conventionally, as build-up wear-resistant copper-based alloys, alloys in which beryllium is added to copper; a copper-nickel-silicon alloy known as the Colson alloy; and dispersion-strengthened type alloys in which hard oxide particles, such as SiO2, Cr2O3 and BeO, are dispersed in copper-based matrices have been known. However, these alloys are such that they are associated with the problem of adhesion, and that the wear resistance does not necessarily have a sufficient characteristic.
Hence, the present applicant developed a build-up wear-resistant copper-based alloy containing zinc or tin, which is more likely to be oxidized than copper. In this one, the adhesion resistance is upgraded by means of the generation of the oxides of zincortin, and the wear resistance of the copper-based alloy improves. However, since zinc or tin is such that the melting point is remarkably lower than copper, it is not necessarily a satisfactory one. Especially, in forming the build-up layers of the aforementioned copper-based alloy using a high-density energy thermal source, such as a laser beam, zinc or tin is likely to evaporate in building up, it has not been easy to maintain the target concentrations of alloying elements. Hence, recently, a build-up wear-resistant copper-based alloy having a composition, which includes nickel: 10.0-30.0%; silicon: 0.5-5.0%; iron: 2.0-15.0%; chromium: 1.0-10.0%; and cobalt: 2.0-15.0%; as well as one member or two or more members of molybdenum, tungsten, niobium and vanadium: 2.0-15.0%; by weight %, has been developed by the present applicant (Patent Literature No. 1, and Patent Literature No. 2). In this alloy, hard particles having Co—Mo system silicides (silicified substances), and Cu—Ni system matrices are the major ingredients. The wear resistance of this build-up wear-resistance copper-based alloy is secured mainly by the hard particles having Co—Mo system silicides, and the cracking resistance of this build-up wear-resistance copper-based alloy is secured mainly by the Cu—Ni system matrices. Even when this alloy is used under severe conditions, the wear resistance is high. Further, since zinc and tin are not used as an active element, the drawback of the evaporation of alloying elements is less even in the case of building up, and the occurrence of fuming, and the like, is less. Accordingly, it is appropriate for alloys for building up, alloys which form build-up layers using a high-density energy thermal source, such as a laser beam, especially.
As described above, even if alloys according to Patent Literature No. 3 and Patent Literature No. 4 are used under severe conditions, they exhibit good wear resistance. Especially, in oxidizing atmospheres or in air, since oxides, which exhibit satisfactory solid lubricating properties, generate, they exhibit good wear resistance.                Patent Literature No. 1: Japanese Unexamined Patent Publication (KOKAI) No. 8-225,868        Patent Literature No. 2: Japanese Examined Patent Publication (KOKOKU) No. 7-17,978        Patent Literature No. 3: Japanese Unexamined Patent Publication (KOKAI) No. 8-225,868        Patent Literature No. 4: Japanese Examined Patent Publication (KOKOKU) No. 7-17,978        